The simple reason why the old 'sell in May' cliche is terrible advice

And so of course we will now hear the old "sell in May and
go away" cliche in markets a
lot more often.

Liz Ann Sonders, chief investment strategist at Charles Schwab,
laid out the data underlying this saying in a
post earlier this week: for the last half century, nearly all
of the S&P 500's gains have happened between October and
April.

Sonders noted that the mean return from May to October was
1.3%.

From November to April, however, the market has returned 7.1%, on
average.

And so returns during the summer are weak, not
negative.

Here's Sonders:

The "strategy" did not work for the three years from
2012-2014, or for the five years from 2003-2007, when there were
gains between May and October in each year ... There is a
meaningful difference between how the market performs from a
seasonal perspective in secular bull or secular bear markets.
Average gains and the percent of positive cases have been higher
in secular bulls than in secular bears (even if they are still
lower than in the November through April period).

In short, returns will generally be higher in a secular bull
market — which we're in now — even if they have a seasonally
tendency to be lower in a particular timeframe.